This proposal deals with the study of the immunoprotective potential of Salmonella typhimurium porins and anti-porin monoclonal antibodies in experimental murine salmonellosis. Groups of mice will be immunized with a panel of 7 anti-OmpD (trimer) and 11 anti-OmpC (trimer) monoclonal antibodies that have been shown to bind to exposed epitopes. A second group of mice will be immunized with Salmonella porins in their native trimeric forms. These mice will be challenged with 2 to 100 LD50 values of virulent S. typhimurium LT-2. The protective efficacy of porins and anti-porin monoclonal antibodies will be determined from 21-day survival data. A third group of mice will be given, orally, a lethal dose of Salmonella accompanied by ascites fluid either with the challenge dose or IP prior to the infectious dose. The number of Salmonella resident in Peyer's patches will be determined at intervals after administration in order to correlate the efficacy of anti-porin monoclonal antibodies given orally to block the invasion of Salmonella.